Ducks speak in Hollywood movies. So it’s forgivable that The King’s Speech, which arrived smooth, sleek and fully formed on movie screens in Canada recently, is scientific balderdash.

The movie accurately tells the story of George VI (Colin Firth), born Albert Frederick Arthur George, alias the Duke of York, the stammering second son of Great Britain’s King George V.

Bertie, as he was popularly known, unexpectedly became George VI when his brother, Edward, abdicated for the bossy charms of Wallis Simpson. That left babbling Bertie to lead Britain to battle with Hitler, which he managed with the help of an Australian speech therapist and commoner named Lionel Logue, who became one of the King’s closest and most unlikely friends.

As director Tom Hooper tells the story, Bertie stuttered because he had a terrifying father who had a terrifying father of his own who was in turn terrorized by his mother. Worse, left-handed Bertie was forced to switch to his right and he was strapped into leg braces to correct his knock knees.

The film implies that these external coercions – and those of being born into a life of duty – knotted his tongue. Which is romantic but false. Scientists now know that stuttering is a neurological condition, possibly genetic, and quite likely the result of lesions in the brain.

“The brain works differently in people who stutter,” Luc De Nil, who heads the University of Toronto’s Department of Speech Pathology, told me this week. “And there’s no question that there’s a strong genetic component.”

A stutterer’s brain goes into overdrive at the mere sight of a thing to be named. This electrical outburst interferes with the way the basal ganglia, which control the smoothness and timing of the movements of the mouth, interact with the cortex, the boss of sequencing.

It’s a common affliction, not just one of repressed bluebloods. One in 20 people stutter, and a fifth of them don’t grow out of it. But 80 per cent can learn to tame the affliction with behavioural speech-control techniques (some of the same ones Lionel Logue used on his famous patient).

“Of course, there’s a strong psychological aspect to it as well,” Dr. De Nil adds, “as people who stutter” – PWSes, as they call themselves – “learn to deal with these dysfluencies, which is when all the tics and secondary behaviours, the muscle tensing and the eye blinks, show up.”

There is newsreel footage of the “cured” George VI addressing a crowd in Scotland in 1938: His discomfort is still agonizingly palpable.

The best help you can offer a stutterer is eye contact and patience. Movies have done that scene too, as when John Cleese hilariously extracts the name of the Cathcart Towers Hotel from stammering Michael Palin in A Fish Called Wanda. Consonants are hardest (“It’s K-K-Ken, c-c-coming to k-k-k-kill me”); nine-10ths of stutters occur at the muscle-tensing starts of words.

Jaan Pill, co-founder of the Canadian Stuttering Association, began stuttering at 6. He was finally treated, in an intensive, three-week program, at 41. “I relearned how to speak,” he says today, at 64. “Or I could say I learned fluency as a second language.” The discovery that his stuttering was neurological, not the result of deep psychological conflict, was a liberation.

Unscientific or not, The King’s Speech works because speechlessness is an ancient and useful metaphor. “There’s a hierarchy of disabilities,” a professor of disability studies said to me the other day. “The blind are on top, of course,” because they can display all their rational faculties. Stuttering has nothing to do with intelligence, but its sufferers are further down that status ladder.

There have been as many hare-brained theories on causes – e.g., too much tickling – as wacko solutions (hit the stutterer full in the face on a cloudy day). But stammering itself is universal, an acting-out of the central human struggle between who we hope to be and what we actually are.

Before the treatment, Geoffrey Rush’s Lionel Logue asks the soon-to-be-king if he really wants to be cured, if he can handle the responsibility and power of a voice. Bertie finds his, only to use it, reluctantly, to lead his people into one of history’s deadliest wars. He must have wondered if the words were worth speaking.